“Non Linear Inverse Liquid Solid Chromatography…” and “Ultrabright Plasmonic-fluor as a Cross-platform "Nanolabel for Femtomolar Detection of Bioanalytes”


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Thursday, October 22, 2020 -
2:00pm to 3:15pm
Mark Schnepper, Ph.D., Postdoctoral Researcher, University of Central Florida, and Jingyi Luan, Ph.D., Research Scientist, Washington University

IMSE presents the North American Materials Colloquium Series:

For the link to the synchronous presentation and live Q&A session (10/22 2-3:15PM or 10/22 3-4:15PM):  RSVP Here

Asynchronously view the presentation ONLY here:  Asynchronous Presentation (link not live yet)

Two presentations will be given in today’s seminar slot:


“Non-Linear Inverse Liquid-Solid Chromatography as a Methodology to Characterize Drug Concentration Losses to Polymeric Materials Used in Body-on-a-Chip Devices for Drug Discovery”

Mark Schnepper, Ph.D.,

Postdoctoral Researcher,

University of Central Florida

Body-on-a-chip and human-on-a-chip systems are currently being used to augment and could eventuallyreplace animal models in drug discovery and basic biological research. However, hydrophobic molecules, especially therapeutic compounds, tend to adsorb to the polymer materials used to create these microfluidic platforms, which may distort the dose-response curves that feed into Pharmacokinetic/Pharmacodynamic (PK/PD) models which translate preclinical data into predictions of clinical outcomes. Adsorption of hydrophobic molecules to these polymer materials needs better characterization.

Inverse Liquid-Solid Chromatography paired with a numerical optimization based on the Langmuir model of adsorption was used to characterize the adsorption isotherm parameters of selected drugs to polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA), polymers commonly used in these platforms after extensive modification to an existing HPLC-MS instrument.Surface modification by organosilanes is one method being explored to modify PDMS, but the effect of organosilaneson drug adsorption isotherms are not well characterized. We utilized Inverse Liquid-Solid Chromatography (ILC) to characterize the adsorption parameters of the selected drugs with native PDMS and organosilane-modified (fluoropolymer (13F) and polyethyleneglycol (PEG)) PDMS surfaces to correlate the modifications to changes in drug adsorption.

Mark Schnepper recently graduated from the University of Central Florida with his Ph.D. in materials science and engineering in the summer of 2020 from Dr. James J. Hickman’s Group. He obtained his masters also at the University of Central Florida in M.S. and engineering in 2014 and his B.S. in chemistry from Whitman College in 2008. Before entering his graduate career, he worked at the Energy Biosciences Institute located on the University of California, Berkeley campus as an analytical chemist from 2009 to 2010.


“Ultrabright Plasmonic-fluor as a Cross-platform Nanolabel for Femtomolar Detection of Bioanalytes”

Jingyi Luan, Ph.D.,

Research Scientist,

Washington University

The detection and quantification of low-abundance molecular biomarkers in biological samples is challenging. Here, we show that a plasmonic nanoscale construct serving as an ‘add-on’ label for a broad range of bioassays improves their signal-to-noise ratio and dynamic range without altering their workflow and readout devices. The plasmonic construct consists of a bovine serum albumin scaffold with approximately 210 IRDye 800CW fluorophores (with a fluorescence intensity approximately 6,700-fold that of a single 800CW fluorophore), a polymer-coated gold nanorod acting as a plasmonic antenna and biotin as a high-affinity biorecognition element. Its emission wavelength can be tuned over the visible and near-infrared spectral regions by modifying its size, shape and composition. It improves the limit of detection in fluorescence-linked immunosorbent assays byup to 4,750-fold and is compatible with multiplexed bead-based immunoassays, immunomicroarrays, flow cytometry and immunocytochemistry methods, and it shortens overall assay times (to 20 min) and lowers sample volumes, as shown for the detection of a pro-inflammatory cytokine in mouse interstitial fluid and of urinary biomarkers in patient samples.

Jingyi Luan, Ph.D., Washington University

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